I am considering to purchase a second hand Revox B-77 reel to reel recorder since my Tandberg TD 20A seems to be difficult to get repaired and don't like some types of tapes. The Tandberg TD 20A mostly like Maxell 1800 ft (7") /3600 ft. (10.5")  tapes and also do a poor job on recording on 7" 2400 ft. tapes that I obtained second hand some time ago. 

Does this seem to be a clever choice or something I should consider, like try to repair my TD 20A one more time?

What kind of tapes is the Revox B77 adjusted for? Is it difficult to repair if anything fails?

Since this is a 33/4 and 71/2 ips machine I guess it is a 4 track machine?
Any idea of how old this machine is?

Hope to get some good advices from you Revox users, since I have no experience with Revox, only Tandberg.
Any observations–thoughts would be most welcome.

All the best